Distribution of HNCO 505−404_{05}-4_{04} in Massive Star-forming Regions

The goal of this paper is to study the spatial distribution of HNCO in massive star-forming regions, and investigate its spatial association with infrared sources, as well as physical conditions in region of HNCO emission. We have mapped nine massive star-forming regions in HNCO 5$_{05}-4_{04}$ with the Purple Mountain Observatory 13.7m telescope. The C18O maps of these sources were obtained simultaneously. The HNCO emission shows compact distribution, with emission peak centred on water masers. Nearly all the HNCO clumps show signs of embedded mid-infrared or far-infrared sources. The FWHM sizes of HNCO clumps are significantly smaller than C18O clumps but rather similar to HC3N clumps. We also found good correlation between the integrated intensities, linewidths and LSR velocities of HNCO and HC3N emission, implying similar excitation mechanism of these two species. As such, collisional excitation is likely to be the dominant excitation mechanism for HNCO 5$_{05}-4_{04}$ emission in galactic massive star-forming regions.Comment: 9 pages, 4 figures, accepted by A&

Planar waveguide CO2 laser amplifiers

The scaling of diffusion-cooled planar waveguide carbon dioxide laser oscillators to very high average power levels (> 5 kilowatts) is limited by mechanical constraints, associated with the physical size of the laser electrodes. Moreover, the operation of such lasers in pulsed mode is limited to pulse duration larger than - 50flS. However, there are important laser applications, for example in material processing, where the requirement is for high peak power level and short pulses combined with high average power. The principal objective of this project is to investigate a laser architecture based on the master oscillator power amplifier concept, but involving planar waveguide gain medium structures. Such an amplifier system may be used either for simple power amplification (long pulse/cw) or for amplifying short pulses using a 'pulse forming' modulator at the input for the amplifier. The laser excitation method involves transverse radio frequency discharges designed to match the large area slab-like structures. This excitation technique would permit multiple "stacked" slab operation with a single power generator, and in the future, may facilitate an "integrated" MOPA construction. The gain and power amplification characteristics of RF discharge excited planar waveguide amplifiers have been investigated over a range of operating parameters (gas pressure, RF power density, input beam intensity etc.) for both pulsed and cw input beams and also for single and multiple (folded) passes of the planar amplifier. Short pulses at the input to the amplifier ('p ~ 1 flSec) were generated using a long pulse oscillator and an acousto-optic modulator as a pulse slicer. In all cases, beam transformation optics were designed and utilised to ensure the excitation of the fundamental waveguide mode with minimal mode coupling. Studies of discharge-induced mode matching effects (phase shifts, amplitude variations) have also been conducted, and techniques for the elimination of parasitic oscillation have been developed. The future potential for the MOP A concept utilising this technology is evaluated for high power laser applications

RÉSISTANCE ET CONFUSION DANS L'HARMONIZATION DES NORMES COMPTABLES INTERNATIONALES : L'APPROCHE CHINOISE AUX FUSIONS ET ACQUISTIONS

Cette communication se concentre sur le cas du comité de normalisation de comptabilité de la Chine (CASC), qui a agi en 2006 de permettre l'utilisation de la méthode de mise en commun des intérêts pour les fusions dans certaines circonstances. Pourtant, cette méthode a été explicitement interdite par le FASB et l'IASB. On discute dans cet article deux questions principales. La première concerne le contexte culturel et économique du développement économique chinois, ce qui a mené les régulateurs chinois à adopter une approche aux regroupements qui diffère de la norme d'IASB. La deuxième traite du rôle joué par la compréhension de la réalité économique qui sous-tende les regroupements. La complexité de la réorganisation industrielle qui trouve actuellement en Chine mène à la réalisation que quelques regroupements sont des fusions et pas des acquisitions. C'est une observation significative qui soit digne d'une plus grande discussion et considération par les régulateurs des normes comptables internationales.IASB, regroupement, méthode d'acquisition, méthode de mise en commun, fusion